This invention relates generally to low viscosity polymeric colorant formulations comprising extremely low amounts of viscosity modifiers that significantly reduce the overall viscosity of the resultant colorant formulation as compared with the viscosity of the colorants themselves. In such a manner, the resultant formulation facilitates the utilization of such polymeric colorants within certain coloring processes and methods requiring low viscosity formulations while simultaneously permitting substantial retention of the same high color strength characteristics of the unmodified colorants. Such an unexpected result thus permits production and utilization of a low viscosity formulation that does not sacrifice colorability to an appreciable degree for target substrates or media. The inventive formulations thus comprise any number of polymeric colorants, (i.e., oxyalkylenated colorants comprising at least one chromophore constituent and at least oxyalkylene chain) and at least one viscosity modifying agent possessing a dipole moment of between 1.0 and 5.0 and/or a flash point of from about xe2x88x9220xc2x0 C. to about 180xc2x0 C. Such a modifying agent provides a significant reduction in viscosity at low levels (to permit better pumpability of the desired colorants) with no appreciable differences in coloring performance within final target media, and facilitates removal of such modifiers during or after utilization. Methods of production, utilization, and products produced with such formulations and by such methods are also encompassed within this invention.
All U.S. Patents cited herein are entirely incorporated by reference.
Polyurethane products, such as foams, resins, and the like, have traditionally been colored by pigments, polymeric colorants, and dyes. Generally, these colorations are performed in situ during foam, resin, etc., formation. For instance, polymeric colorants (i.e., polyoxyalkylenated colorants), such as those described in U.S. Pat. No. 4,284,279 to Cross et al., have been introduced within polyol compositions during slabstock foam production. The xe2x80x9ccoloredxe2x80x9d polyol then reacts with an isocyanate composition, in the presence of a catalyst possibly, to form the desired colored foam. Pigments have also been added in the past, most notably in solid, paste, or powder form, to a polyol stream to form the same type of colored foam products. Such compounds are readily available and inexpensive; however, they also exhibit or create problems during handling, mixing (with other pigments to create different shades, for example), and actual incorporation within target media. Furthermore, pigments, being solid in nature, tend to from clumps of solids within target media that leads to aesthetically displeasing consequences or clogging of machinery or instrumentation. Additionally, spills are likely (since the powder or solid form of such pigments do not transport easily due to atmospheric conditions and possible air disturbances), and clothes or hand staining by difficult-to-handle pigment compounds is very likely to occur through the utilization of such solid coloring agents. Also, such pigments are not storage-stable in liquid form, generally, and appear to easily precipitate out of solution after even a short shelf storage duration. Furthermore, such pigments are difficult to control from a uniformity standpoint such that the ultimate polyurethane product may exhibit uneven colorations without proper and time-consuming prior mixing. As such, polymeric colorants have proven to be more desirable than powdered or solid pigments as coloring agents within such polyurethane coloring processes.
Also, thermoplastics have been colored with polymeric colorants in the past, such as in U.S. Pat. No. 4,640,690 to Baumgartner et al. Such colorants have proven quite useful and beneficial in their high coloring and low migratory and blooming properties. Pigments have also been utilized for such coloring processes; however, the use of solid and/or powders has, again, suffered from the same handling, precipitation, and uneven coloring problems, particularly in industrial operations. Polymeric colorants are thus more desirable for these procedures as well.
Also utilized to color certain thermoplastic substrates are quaternary ammonium/anionic dye complexes, such as those disclosed within U.S. Pat. Nos. 5,938,828 and 5,948,152, both to Zhao et al. Such colorants provide excellent tinting of thermoplastic compositions but also suffer from high viscosity problems in pumpability, etc., within the necessary machinery.
One drawback in the utilization of such polymeric and/or quat/anionic dye colorants, which are present as either liquids or waxes primarily, but may also exist as solid or very highly viscous pastes, is the difficulty in preparing suitable physical forms of such colorants for universal utility within desired processes. For instance, slabstock foam production requires either a high or low pressure pumping mechanism to introduce such colorants within a polyol stream. If the viscosity of the colorants is too high, such pumping may be deleteriously effected and the coloring procedure may prove too difficult to accomplish or the final product may, as with some pigments, exhibit uneven colorations. Low, and/or controlled, viscosity colorants are thus necessary to facilitate simple modifications of such beneficially coloring colorants for introduction within a variety of different coloring procedures. To date, the great majority of modifications to polymeric colorant viscosities have been accomplished through the physical admixing of large amount of viscosity modifiers, such as, for example FOMREZ(copyright), a ? available from ? Although viscosity modifications have been provided with such agents, the overall color strength available to the end-user has been sacrificed. Thus, the desired colorants were modified for utilization within myriad processes (such as polyolefin, polyester, polyurethane, and the like, coloring methods) in the past, but greater amounts of such low viscosity colorant were required to provide the desired coloring strength (and thus coloring effects) within the target substrates and/or media. (For this invention, the term xe2x80x9ccolor strengthxe2x80x9d is intended to encompass the degree of color available for introduction within a target composition per actual volume of colorant present, otherwise known as color value. Such a color value is thus directly related to the actual amount of colorant present within the colorant composition.) The greater amount of low viscosity colorant required, the greater the cost to the end-user, and ultimately, to the consumer. There is thus a need to provide a reduced viscosity polymeric colorant composition which does not lose any appreciable degree of color strength upon attaining the desired viscosity level. To date, no such improvement has been accorded this industry by the prior art.
It is therefore an object of this invention to provide a high color strength, low viscosity, polymeric colorant-comprising composition that also comprises extremely low amounts of viscosity reducing agents. A further object is to provide a polymeric colorant composition that exhibits a significant reduction in viscosity with an extremely low amount of viscosity reducing agent, which does not deleteriously effect the desired coloring procedure, present. A further objective of this invention is to provide a extremely low viscosity polymeric colorant composition that retains substantially the same general color value as a high viscosity composition comprising the same polymeric colorant, wherein the colorant is present in the low viscosity composition in an amount nearly the same as that of the high viscosity colorant.
Accordingly, this invention is directed to a nonaqueous liquid composition comprising at least one polymeric colorant containing composition and at least one viscosity modifying compound exhibiting a dipole moment of between about 1.0 and 5.0 or, alternatively, exhibiting a flash point of between about xe2x88x9220xc2x0 C. and 180xc2x0 C. Preferably, though not necessarily, the viscosity modifying compound is aprotic in nature; although glycols do seem to function properly to significantly reduce the viscosity of the target polymeric colorant composition, their presence within certain target media (such as polyurethanes) is undesirable due to the presence of reactive hydroxyls on such compounds. The methods of production of such compositions are also contemplated within this invention. The term xe2x80x9cliquid compositionxe2x80x9d is intended to encompass any composition which is present in a fluid state (i.e., possessing a viscosity of below about 10,000 centipoise at standard temperature and pressure).
The term xe2x80x9cnonaqueousxe2x80x9d denotes a composition into which no water has been specfically introduced. Due to the possibility of atmospheric water being introduced through exposure to a relatively humid environment, this term does not rule out the potential for any water to be present through such a manner. The term xe2x80x9cliquid dispersionxe2x80x9d is intended to encompass any composition which is present in a fluid state (i.e., possessing a viscosity of below about 10,000 centipoise at standard temperature and pressure). The term xe2x80x9caproticxe2x80x9d is well known within the chemical arts and simply means that no protons can be accepted or donated by the specific compound. As such, it is imperative that certain moieties not be present on the intended viscosity modifying compound. Such unwanted moieties include, without limitation, acid groups, hydroxyls, amines, and the like. However, as noted above, this list is not definitive; any aprotic compound possessing the required dipole moment property is included in this definition.
The dipole moment requirement for the viscosity modifying compound is necessary to provide the desired performance characteristics for the inventive nonaqueous low viscosity liquid polymeric colorant containing compositions. It has been found, surprisingly, that the selection of a relatively low dipole moment viscosity modifying compound provides the desired drastic lowering of overall viscosity with minimal amounts of viscosity modifying material, thus providing the desired high color retention. Furthermore, due to the low dipole moment, the corresponding flash point of the viscosity modifying compound is also relatively low in order to permit removal of such a compound upon introduction within a coloring method utilizing relatively low processing temperatures. As such, since the aprotic compound must exhibit a low flash point, and dipole moments have not been recorded for all compounds which may function in this capacity within the inventive dispersions, the viscosity modifying compound may alternatively be defined in relation to its aprotic nature and its flash point. Thus, a flash point of between about xe2x88x9220xc2x0 C. and 180xc2x0 C. is necessary; preferably such a level is between 0xc2x0 C. and 165xc2x0 C.; more preferably from 80xc2x0 C. to about 160xc2x0 C.; most preferably between about 95xc2x0 C. and 145xc2x0 C. Such an aprotic compound thus does not affect any production methods (such as, as merely one example, polyurethane coloring through initial introduction within a polyol composiiton followed by admixing with an isocyanate; at low heat exposures, the viscosity modifying compound will evaporate from the final composition with relative ease). It is also preferable that the selected aprotic viscosity modifying compound (or compounds) be liquid in nature and exhibit a viscosity of at most 500 centipoise at standard temperature and pressure (i.e., 25xc2x0 C. at 1 atmosphere) as measured by a Brookfield Viscometer. This requirement facilitates handling (particularly in large-scale industrial applications) and more easily permits production of the desired viscosity level for the nonaqueous liquid composition itself.
Also determined to be of great importance to the selection of a proper viscosity modifying compound within the inventive nonaqueous liquid pigment dispersion is the molecular weight of such a compound. Due to the low dipole moment (which concerns the low polarity of the compound itself), and/or the low flash point necessary for such a compound, the molecular weight must also be rather low. Thus, a molecular weight of at most 200 is available for the inventive dispersion; preferably, this weight is at most 150; more preferably, at most about 120; and most preferably, between about 85 and 116.
Such specific compositions provide low-viscosity compositions comprising highly desirable high color value polymeric colorants. In the past, as noted above, the necessity of reducing the viscosity of polymeric colorant-containing compositions in order to permit utilization within certain processes resulted in a severe reduction in the amount of colorant actually present within the low viscosity formulation. As a result, the available color value for such a low viscosity composition was sacrificed in order to provide a more versatile colorant composition. This loss of color value detrimentally affects the costs involved in the production of such target substrates or media since greater amounts of low viscosity colorant composition had to be introduced in order to effectuate an acceptable color shade. The inventive compositions alleviate such a problem by providing a low viscosity formulation of large amounts of intrinsically high viscosity polymeric colorants (which thus exhibit high color strength characteristics). Thus, lower amounts of low viscosity colorant compositions may thus be utilized to provide acceptable color levels to target substrates or media in comparison with the aforementioned previously utilized low viscosity formulations. Such an improvement is quite significant as the versatility and costs involved with such polymeric and/or quat/anionic dye colorants are increased and decreased, respectively. Thus, the inventive compositions of such colorants and low dipole moment compounds provide significant reductions in viscosity (such as a viscosity reduction of about 50% as compared with the non-modified colorant with a small amount of low dipole moment modifier present, such as about 1 to about 5% by weight).
The term xe2x80x9cpolymeric colorantsxe2x80x9d is intended to encompass any colorant which possesses, as constituent moities, chains of at least two alkyleneoxy groups. Such a term is widely known and used within the colorant industry and thus would be easily understood and appreciated by the pertinent ordinarily skilled artisan. Preferably, such colorants meet any structure defined by Formula (I)
R{A[(B)nR1]m}xxe2x80x83xe2x80x83(I)
wherein
R is an organic chromophore;
A is a linking moiety in said chromophore selected from the group consisting essentially of N, O, S, SO2N, and CO2;
B is selected from the group of one or more alkyleneoxy constituents containing from 2 to 4 carbon atoms;
n is an integer of from 2 to about 100;
m is 1 when A is O, S, or CO2, and m is 2 when A is N or SO2N;
x is an integer of from 1 to about 5, preferably 1 or 2; and
R1 is selected from the group consisting of H, C1-C4 alkyl, C10-C22 fatty ester, a C1-C20 alkenyl succinic anhydride moiety, and any mixtures thereof. The organic chromophore may be of any standard type, including, without limitation, anthraquinone, methine, azo, disazo, trisazo, diazo, nitroso, triphenylmethane, diphenylmethane, xanthane, acridine, indamine, thiazole, or oxazine. Preferably, R is one or more of triphenylmethane, methine, azo, or thiazole based compounds. Group A is present on group R and is utilized to attach the polyoxyalkylene constituent to the organic chromophore. Nitrogen is the preferred linking moiety. The polyoxyalkylene group is generally a combination of ethylene oxide and propylene oxide monomers. Preferably propylene oxide is present in the major amount. The preferred number of moles of polyoxyalkylene constituent per chain (B) is from 2 to 15 (n would therefore preferably be from 4 to 30), more preferably from 4 to 10 (n would most preferably be from 8 to 20). Also, preferably two such polyoxyalkylene chains are present on each polymeric colorant compound (x, above, is preferably 2). Group R1 is preferably hydrogen; however, C16-C18 fatty esters are also highly preferred.
As noted above, also useful as colorants within this inventive composition are purified quat/anionic dye types as disclosed within U.S. Pat. Nos. 5,938,828 and 5,948,152, either alone or incombination with the polymeric colorants noted above.
The colorants utilized within the present invention are generally liquid at ambient conditions of temperature and pressure, although they are generally highly viscous liquids (i.e., greater than about 6,000 cps, more likely higher than about 9,000 cps. As discussed above, in order to permit or improve pumpability of these colorants within and/or into certain coloring processes, the viscosities thus must be reduced significantly. Most mechanisms required to incorporate such polymeric colorants within target media (for example, mixheads and/or feed tank pipes for adding pigments within polyurethane foam production methods) utilize certain pumps and feed lines that are highly sensitive to pressure provided by higher viscosity compositions. With lower and possibly more uniform viscosities between utilized colorant compositions, versatility of colors increases, thereby providing an overall improved ability to produce desirable end products. Such low viscosity may be (and has been) provided through the introduction of a solvent or viscosity modifier at a point in time near to the actual incorporation of the dispersion within the target media (for polyurethane, the addition would take place either within the polyol component or within the isocyanate component; the two components are mixed together with catalysts to form the desired polyurethane foam). However, this late introduction adds to the complexity and potential problems facing the user in producing such dispersions, again, and particularly, at the industrial level. Thus, a storage stable, low viscosity polymeric colorant containing composition is highly desired; unfortunately, such compositions have not been available until this recent development.
The inventive nonaqueous liquid compositions exhibit a number of surprising characteristics that lend themselves to a suitable inexpensive, yet highly effective, coloring formulation, particularly for polyurethane foams. Storage stability, without any phase separation between liquid components, is of utmost importance with such compositions. The retention of extremely low viscosities, without any noticeable or, at least significant, increase, over a long duration, thus provides a highly desired, easy-to-handle product. Without intending to be bound to any scientific theory, it is believed that such storage stability is provided through the interaction of the specifically selected aprotic viscosity modifiers with the target liquid colorants by preventing reactions or attraction between reactive groups (hydroxyls, for example) on the colorants themselves and, since the viscosity modifying compounds are aprotic, not reacting with the colorants. Additionally, the polyurethane foams produced with such inventive dispersions do not exhibit any appreciable losses in color or shade depth in comparison with standard non-modified pigment dispersions nor extraction of the modifying agents after prolonged use or exposure to harsh conditions (i.e., methanol, salt water, etc.). Other impressive similarities between such viscosity modified and non-viscosity modified pigment dispersions are discussed in greater detail below. Succinctly, the inventive dispersions provide improved processability over non-modified polymeric colorant compositions, as well as simultaneous storage stability, all without any appreciable loss in performance as compared with the same non-modified polymeric colorant compositions. Such highly unexpected benefits are of enormous importance to improving upon the available process conditions for applications requiring polymeric colorant utilization.
Particularly preferred colorants, and thus merely examples of the polyoxyalkylene polymeric colorant and/or quat/anionic dye colorant of this invention, include the following: